Discussion
Well I have had the gto for 10 days now, just got it back from Vegan on friday( reroute throttle cable,fluid change etc) nice bunch of guys. On the way back to sunny Gloucestershire I noticed ( and got a passenger to check) that I seem to be only getting around 0.2 to 0.3 bar of boost. Just wondering if any of you had the same problem? It had a new ECU in april it is a late 2002 3.0 gto 3. Also if it is a mapping issue, has anyone had a good remap done (more power,drivability??) heard the name Joust metioned but not found any details. Many thanks in advance for any help.
On a side note spoke to Paul at Vegan - he was quite happy for me to take it back, just I am not due to go to London for a few weeks.
On a side note spoke to Paul at Vegan - he was quite happy for me to take it back, just I am not due to go to London for a few weeks.
alex s said:
Well I have had the gto for 10 days now, just got it back from Vegan on friday( reroute throttle cable,fluid change etc) nice bunch of guys. On the way back to sunny Gloucestershire I noticed ( and got a passenger to check) that I seem to be only getting around 0.2 to 0.3 bar of boost. Just wondering if any of you had the same problem? It had a new ECU in april it is a late 2002 3.0 gto 3. Also if it is a mapping issue, has anyone had a good remap done (more power,drivability??) heard the name Joust metioned but not found any details. Many thanks in advance for any help.
On a side note spoke to Paul at Vegan - he was quite happy for me to take it back, just I am not due to go to London for a few weeks.
Hi Alex, my mapping was redone by Roush via Vagantune. Might be worth contacting Yellowshed, he on here somewhere and did the original mappings AFIK. It certainly transforms the 2.5............
BTW Joust is Justin F's PH alias. However his suggestion will just be to buy an upgraded 2.5
>> Edited by stuh on Monday 6th September 18:17
Joust is me 
(AKA as Justin, J or Oi!)
Roush Techologies (www.roush.co.uk/) did most of the work mapping Noble's engines lately. Yellowshed (AKA Trevor) is the person who's ability to perform magic given a lowly ECU and some plumbing is just amazing.
However, it sounds like the wastegate is "sticking" open or you have a leak around it. The wastegate on my upgraded 2.5l is "digitally" controlled to enable different BAR settings to be achieved depending on what's happening (to give you an idea I often see 0.9bar and it's been known to go over 1 bar to 'get the baby going' when you floor it
)
To me it sounds as if something is amiss, so a trip back to the guys at Vengatune unfortunatly sounds the correct thing to do.
Of course Trevor may be along soon and tell me I'm talking twaddle, but from what I've gleaned from his postings that sounds the most likely thing.
J
(AKA as Justin, J or Oi!) Roush Techologies (www.roush.co.uk/) did most of the work mapping Noble's engines lately. Yellowshed (AKA Trevor) is the person who's ability to perform magic given a lowly ECU and some plumbing is just amazing.
However, it sounds like the wastegate is "sticking" open or you have a leak around it. The wastegate on my upgraded 2.5l is "digitally" controlled to enable different BAR settings to be achieved depending on what's happening (to give you an idea I often see 0.9bar and it's been known to go over 1 bar to 'get the baby going' when you floor it
) To me it sounds as if something is amiss, so a trip back to the guys at Vengatune unfortunatly sounds the correct thing to do.
Of course Trevor may be along soon and tell me I'm talking twaddle, but from what I've gleaned from his postings that sounds the most likely thing.
J
Agreed, either the wastegate is stuck open or opening too early ( it is more likely if this is an internal wastegate IMO) or you ave a "boost leak" .. which would be anywhere in the pressurized systems. Most common spots are at intercooler piping couplers (the connecting pieces can crank very sliggtly or very much so ... or high pressure and or a bump in the orad can cause them to come loose and expose a leak). There could be a leak on the intercooler or on the intercooler pipes.
These are the two most common issues, for this symptom, with a turbo-charged motor.
HTH.
These are the two most common issues, for this symptom, with a turbo-charged motor.
HTH.
Yellowshed
I had a similar low boost problem in my 3R when it would not boost over .5 bar - two new exhaust manifolds later and a new turbo and things are much better! Quick throttle openings in all most gears sees the boost rise rapidly (much better now that I ever remember it before) at some points nudging .9 and nearly 1 bar before settling down.
However it still settles down to no more than .5 in third, .5 and a bit in fourth, .6 in fifth, and it just about gets .7 in sixth. I spoke to the factory and they were confused by this to say the least. It need to go back some time I guess.
Any thoughts as to what may be causing this?
I had a similar low boost problem in my 3R when it would not boost over .5 bar - two new exhaust manifolds later and a new turbo and things are much better! Quick throttle openings in all most gears sees the boost rise rapidly (much better now that I ever remember it before) at some points nudging .9 and nearly 1 bar before settling down.
However it still settles down to no more than .5 in third, .5 and a bit in fourth, .6 in fifth, and it just about gets .7 in sixth. I spoke to the factory and they were confused by this to say the least. It need to go back some time I guess.
Any thoughts as to what may be causing this?
For alex's issue, my diagnosis is 99% accurate. Thee is little else that it could be.
I am not sure what yellow means by "leaky wastgate" because wastegates are designed to "leak" to exhaust past the turbine to maintain a certain boost level .. and they are tuned to leak properly.
A malfunctioning wastegate ... (sticking open or opening too early due to improper pressure signal or electronic solenoid control) could be the issue. The other issue could be anywhere in the intercooler and intercooler pipe system .. where the compressed air would be leaking out before entering the engine.
There is little else that would likely be the issue.
When I hear/see somebody say "leaky wastgate" I think of cracks on the hotside housing of the turbo that surround the wastegate (common in smaller turbos that push high heat/boost). This, however, would not likely be large enough cracks to make for such a low boost issue. A cracked housing area around the wastegate normally leads to signs of boost decreasing with revs ... after hitting the set psi.
This is just typical though, and you could have an issue that is less common ... but I doubt it.
Less common problems could be leaky exhaust manifolds, that would basically act like an open wastegate ... by not letting enough exhaust gas power the turbine.
As for ar-gto,
Do you notice if the bost falls off at certain rpms only .. or if it will fall off even if helpd at a steady rpm? You may be holding proper boost until more revs bring more air that the turbine or exhauist cannot flow. But, if you notice the drop without the revs then it is more likely a leak on the exhaust portion of the pressurized system ... most likely due to wastegate control issue ... and hopefully less likely your newly replaced manifolds.
With the boost settline issues ... they are normally due to some sort of restriction or incorrect wastegate control.
Also, you have some wastegate control issue if your boost is "spiking" like you say .. when it will exceed the desired boost level .... then drop to accurate setting.
A ideal and properly functioning system should raise to a set point and never be at any other pressure.
See the "acceleration thread".
The t-25s and t28s are pretty darn small turbos in comparison to many .. although I do not know the exact specs of the ones used on the Noble.
Possible issues could be that the turbine (exhaust side wheel) is not efficient enough to flow the boost levels set.
In this scenario, the turbine simply cannot keep up with the amount of exhaust flow coming out (which is increased by the compressor wheel when you raise boost as well).
The turbine will not be able to maintain the flow for long at all ... and will slow itself .. therefore decreasing your boost levels.
The exhaust housing restriction can also contribute to this.
A generally cheap solution is to bore out the exhaust housing a bit (but not too thin where it would crack under tuned exhaust temperature) AND to clip the turbine wheel by certain smnall degree so that it will flow more.
The bore in the housing can help with spool time and top end flow.
The clip on the turbine can increase lag time by a small amount ... but sustain boost levels to redline.
Performance Techniques is who I would recommend for such turbo mods if you were interested. But you may not want to use them due to your location. PT is in the USA ... in California.
Another possibility is that your exhaust and or intake are actually too restrictive.
For a turbo-charged motor, the less intake and exhaust restriction the better (unlike NA motors usually are better with a 2.5 inch exhasut for enough restriction to maintain good torque).
The turbo provides all of the restriction necessary for the torque.
The most common size exhaust for a turbo vehicle running under 600hp ... is a 3 inch inner diameter piping from turbo back.
Also, not everyone realises, that if you separate the wastgate blow by from the main exhauist stream by making dump tube that vent to atmosphere .. or even return it to the exhaust (for emissions purposes .. because a dump to atmosphere sounds better and is sure to eliminate turbulance)further down the exhaust stream ... you can noticeably inprove exhaust flow for better spool time/top end flow/ and overall power gains ... because you decrease ehast gas turbulance and allow the exhaust to flow more smoothly and therefore exit more efficiently.
If you wanted, a 3.5-4inch exhaust should spool the turbos even faster and provide for even beter flow. On a turbo motor, torque is really lost only by a miniscule amount if at all form the large exhaust. Many people will run with no exhaust or ... what they call "open downpipe" where a few feet of large diameter pipe simply carry gasses out from the engine bay and dump to atmosphere.
Problems with this larger exhaust tend to be clearance issues in the engine bay and in relation to the ground (although a open downpipe is much les likely to have this issue).
I find it very interesting that "the factory" would not be able to tell you such things about a turbocharged motor.
Then again, maybe you were just speaking with the wrong people. A car salesman or management is less likely to understand how turbocharged flow with a motor works and common issues with the setups. I know nothing about the "talent" at any of the manufacturers or dealers.
HTH.
I am not sure what yellow means by "leaky wastgate" because wastegates are designed to "leak" to exhaust past the turbine to maintain a certain boost level .. and they are tuned to leak properly.
A malfunctioning wastegate ... (sticking open or opening too early due to improper pressure signal or electronic solenoid control) could be the issue. The other issue could be anywhere in the intercooler and intercooler pipe system .. where the compressed air would be leaking out before entering the engine.
There is little else that would likely be the issue.
When I hear/see somebody say "leaky wastgate" I think of cracks on the hotside housing of the turbo that surround the wastegate (common in smaller turbos that push high heat/boost). This, however, would not likely be large enough cracks to make for such a low boost issue. A cracked housing area around the wastegate normally leads to signs of boost decreasing with revs ... after hitting the set psi.
This is just typical though, and you could have an issue that is less common ... but I doubt it.
Less common problems could be leaky exhaust manifolds, that would basically act like an open wastegate ... by not letting enough exhaust gas power the turbine.
As for ar-gto,
ar-gto said:
Quick throttle openings in all most gears sees the boost rise rapidly (much better now that I ever remember it before) at some points nudging .9 and nearly 1 bar before settling down.
However it still settles down to no more than .5 in third, .5 and a bit in fourth, .6 in fifth, and it just about gets .7 in sixth. I spoke to the factory and they were confused by this to say the least. It need to go back some time I guess.
Any thoughts as to what may be causing this?
Do you notice if the bost falls off at certain rpms only .. or if it will fall off even if helpd at a steady rpm? You may be holding proper boost until more revs bring more air that the turbine or exhauist cannot flow. But, if you notice the drop without the revs then it is more likely a leak on the exhaust portion of the pressurized system ... most likely due to wastegate control issue ... and hopefully less likely your newly replaced manifolds.
With the boost settline issues ... they are normally due to some sort of restriction or incorrect wastegate control.
Also, you have some wastegate control issue if your boost is "spiking" like you say .. when it will exceed the desired boost level .... then drop to accurate setting.
A ideal and properly functioning system should raise to a set point and never be at any other pressure.
See the "acceleration thread".
The t-25s and t28s are pretty darn small turbos in comparison to many .. although I do not know the exact specs of the ones used on the Noble.
Possible issues could be that the turbine (exhaust side wheel) is not efficient enough to flow the boost levels set.
In this scenario, the turbine simply cannot keep up with the amount of exhaust flow coming out (which is increased by the compressor wheel when you raise boost as well).
The turbine will not be able to maintain the flow for long at all ... and will slow itself .. therefore decreasing your boost levels.
The exhaust housing restriction can also contribute to this.
A generally cheap solution is to bore out the exhaust housing a bit (but not too thin where it would crack under tuned exhaust temperature) AND to clip the turbine wheel by certain smnall degree so that it will flow more.
The bore in the housing can help with spool time and top end flow.
The clip on the turbine can increase lag time by a small amount ... but sustain boost levels to redline.
Performance Techniques is who I would recommend for such turbo mods if you were interested. But you may not want to use them due to your location. PT is in the USA ... in California.
Another possibility is that your exhaust and or intake are actually too restrictive.
For a turbo-charged motor, the less intake and exhaust restriction the better (unlike NA motors usually are better with a 2.5 inch exhasut for enough restriction to maintain good torque).
The turbo provides all of the restriction necessary for the torque.
The most common size exhaust for a turbo vehicle running under 600hp ... is a 3 inch inner diameter piping from turbo back.
Also, not everyone realises, that if you separate the wastgate blow by from the main exhauist stream by making dump tube that vent to atmosphere .. or even return it to the exhaust (for emissions purposes .. because a dump to atmosphere sounds better and is sure to eliminate turbulance)further down the exhaust stream ... you can noticeably inprove exhaust flow for better spool time/top end flow/ and overall power gains ... because you decrease ehast gas turbulance and allow the exhaust to flow more smoothly and therefore exit more efficiently.
If you wanted, a 3.5-4inch exhaust should spool the turbos even faster and provide for even beter flow. On a turbo motor, torque is really lost only by a miniscule amount if at all form the large exhaust. Many people will run with no exhaust or ... what they call "open downpipe" where a few feet of large diameter pipe simply carry gasses out from the engine bay and dump to atmosphere.
Problems with this larger exhaust tend to be clearance issues in the engine bay and in relation to the ground (although a open downpipe is much les likely to have this issue).
I find it very interesting that "the factory" would not be able to tell you such things about a turbocharged motor.
Then again, maybe you were just speaking with the wrong people. A car salesman or management is less likely to understand how turbocharged flow with a motor works and common issues with the setups. I know nothing about the "talent" at any of the manufacturers or dealers.
HTH.
m12_nathan said:
I think your points about how much air the turbos can flow would be more relevant to a modified car, not a standard car when other owners aren't getting the same issues...
HTH
m12_nathan said:
I think your points about how much air the turbos can flow would be more relevant to a modified car, not a standard car when other owners aren't getting the same issues...
HTH
Not necessarily true at all. This motor is already modifed with a twin turbo setup. What I am saying is accurate. I don't like to spread misinformation so I try not provide any input at all unless I am confident. Those are all accurate possibilities for diagnosis and repair.
You guys are talking about elevated boost levels .. which greatly increase chances of flow issues.
Heck even in stock supras .. at completely stock boost .. you can notice boost falling off in higher revs .. simply because of the turbin efficiency .. or lack of efficiency.
Many cars can and do have these issues.
How much air the turbos flow in it's efficiency range is VITAL for anything that has a turbo in use.
I would definitely agree though, that is less likley the issue at all if other owners are running the same setups and boost levels and are positively not experiencing the same symptoms. So, then eliminate the specific turbo issues as the culprit and look elsewhere.
I was simply providing possibly issues and solutions. I do not claim to have most definitely diagnosed and found a solution at all.
I was only hoping to help ... and I did provide potential diagnosis and solutions .. which would/should/does help.
I humbly provide this information, simply to help share some info.
Thanks Guys for all your input, went for a drive today ( with a passenger)And the boost is very consistant at .25bar, if it was a "leaking pipe/wastegate would it be that consistant?? Getting a bit worried as this is starting to sound expensive!! Looks like a 350 mile round trip to see Paul on Sat. Yellowshed, thanks for the offer for help on this, has paul got your contact details? Once again, thanks everyone for your time and suggestion on this. Its nice to see a group of people help each other out just for the love of the marque/car.
Np.
The consistancy is possible with leaks ... but less likely. From what I have seen though .. all the piping is drmatically exposed .. so look around if you get a chance.
It really could be anything that I mentioned. Being that it is holding consistant makes me think that the leak has more to do with the wastegate malfunction only ... but this is no guaruntee.
Good luck! It'll work out. If you know of any great tuners in your area ... describe more to them ... and maybe stop by their shop. I am sure they'd love to take a look after you told em it was a Noble ... lol.
Consult with whoever you want and compare information and price quotes if you are concerned with good service.
Just my 2 psi.
My sincere best regards.
The consistancy is possible with leaks ... but less likely. From what I have seen though .. all the piping is drmatically exposed .. so look around if you get a chance.
It really could be anything that I mentioned. Being that it is holding consistant makes me think that the leak has more to do with the wastegate malfunction only ... but this is no guaruntee.
Good luck! It'll work out. If you know of any great tuners in your area ... describe more to them ... and maybe stop by their shop. I am sure they'd love to take a look after you told em it was a Noble ... lol.
Consult with whoever you want and compare information and price quotes if you are concerned with good service.
Just my 2 psi.
My sincere best regards.
alex s said:Yep - I can confirm (as Trevor will also confirm) that problems are very very consistent with the setup that these cars run.
Thanks Guys for all your input, went for a drive today ( with a passenger)And the boost is very consistant at .25bar, if it was a "leaking pipe/wastegate would it be that consistant?? Getting a bit worried as this is starting to sound expensive!! Looks like a 350 mile round trip to see Paul on Sat. Yellowshed, thanks for the offer for help on this, has paul got your contact details? Once again, thanks everyone for your time and suggestion on this. Its nice to see a group of people help each other out just for the love of the marque/car.
Vengatune, like all of the new authorised service centres, are very very capable with this. One thing that contiously enamours me to the marque is that the technical knowledge on the cars is with a small, dedicated, select set of individuals.
I've had all of the "top 5" people, including Trevor, email and/or talk to me direct about the car, its problems, and what they are doing to fix it.
Rest assured, despite my own actions wiping out an entire engine, I've never been faced with an "expensive" bill. Sure, this car, like any £50k+ car, isn't 'cheap' to run (my X5 service 20000 service was more than the 20k Noble service to put it in perspective), and a large number of "serious" faults are actually very simple and very straight forward to fix.
I've not used Vengatune, but I know lots of people that have and had excellent service. Mole V who I use are often (much to my amazement) saying that they have done "X" or "Y", but when I look at the bill there seems to be no corresponding line item for the labour and/or parts (just don't tell Charles otherwise he might send me a bill
) Pop it back and I am sure that it'll be a simple fix. Unfortunatly there is a heck of a lot of "plumbing" down there, and the smallest leak can lead to what you are expieriencing.
If you want to check yourself, flip the back and pull on every bit of silicon hoseing you can find. I've found (through no-ones fault, just one of those things) that they sometimes come loose due to the oil that runs down them.
If you want some more pointers, email me, and I'll send you some piccies of what I've found over the years and then you can check your car against the pictures.
J
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